Misuse of opioids and other psychoactive drugs during pregnancy is a significant problem in the US. Neonatal abstinence syndrome (NAS) affects most infants exposed to opioids in utero, although its expression is variable. Optimal treatment of NAS has not been established and the current clinical approach is to treat all infants born to mothers taking opioids as being at risk of developing NAS, using standard observation protocols followed by treatment when symptoms of NAS appear. This is clearly sub-optimal because low risk infants remain in the hospital too long while high risk infants have significant delays in the initiation of appropriate drug therapy. Since our group has shown that genetic factors in the mother and infant are emerging as crucial components of NAS, it would be highly significant if clinical, demographic and genetic risk factors could be combined to better identify infants at risk of developing NAS. It would also be important to determine if epigenetic patterns and neonatal neurobehavior change after treatment. The overarching hypothesis is that more comprehensive integration of clinical and genetic factors will better identify infants at risk of significant NAS and guide treatment that will ultimately improve outcome. Two hundred mothers taking opioids and other drugs during pregnancy will be studied along with 200 infants treated for NAS and 100 infants who are exposed to opioids, but do not develop NAS. Clinical, demographic, and genetic data will be collected and risk assessment models of NAS will be developed. In addition, we wish to determine if epigenetic and neurobehavioral factors correlate with the onset and severity of NAS. Epigenetic alterations and Neonatal Network Neurobehavioral Scale (NNNS) scores will be analyzed shortly after birth and again after therapy has been discontinued in 50 infants who require treatment for NAS as well as 50 exposed infants who do not require treatment. We wish to determine if DNA methylation and NNNS scores differ between those who need treatment for NAS and those who do not and if methylation patterns and neurobehavior are altered after treatment. The long term goal of these studies is the development of a clinical prediction tool to establish risk of NAS. While some candidate variables for the prediction tool are already known to be associated with NAS, others are suspected and require confirmation, and others remain to be discovered. By identifying these clinical and genetic risk factors, we should be able to better understand the impact of maternal opioid and other medication use on the variability that exists in NAS.